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310S 321 347H Stainless Steel Seamless Boiler Tubing for High Temperature Power Generation Applications
310S 321 347H Stainless Steel Seamless Boiler Tubing for High Temperature Power Generation Applications
Specifications
OD Range :
6mm - 610mm (1/8 inch - 24 inch)
Delivery Time :
5-7 days for stock, 15-25 days for mill production
Standard :
ASTM A312, ASTM A213, ASME SA312, EN 10216-5
Stabilization Ratio :
Ti/C ratio >=5 (321/321H), Nb+Ta/C ratio >=10 (347/347H)
Payment Terms :
T/T,L/C,D/P,Western Union
Certification :
ISO 9001, EN 10204 Type 3.1, ASME SA312
Wall Thickness :
0.8mm - 40mm (SCH 10S - SCH XXS)
Brand Name :
Baosteel, TISCO
Max Service Temperature :
1050 deg C (310S continuous), 870 deg C (321H/347H continuous)
MOQ :
50 meters
Place of Origin :
China
Price :
USD 4.50-35.00 / kg (Grade and Size Dependent)
Grain Size :
ASTM 7 or coarser (H-grade per ASME SA312)
Packaging Details :
End-capped with plastic protectors, bundled with steel straps; wooden crates for thin-wall and small-OD pipes
Material Grade :
TP310S, TP321, TP321H, TP347, TP347H
Model Number :
SS-SMLS-HT-347H
Supply Ability :
3000 tons per Month
Description

Our high temperature and pressure resistant stainless steel seamless pipes are engineered for critical service in power generation, petrochemical reforming, and industrial boiler applications where operating temperatures routinely exceed 600°C and design pressures reach 250 barg or higher. Available in ASTM A312 TP310S, TP321, TP321H, TP347, and TP347H, these austenitic stainless steel grades provide exceptional creep strength, oxidation resistance, and microstructural stability under sustained thermal and mechanical loading.

Product Specifications

ParameterDetails
Material GradesTP310S (UNS S31008), TP321 (UNS S32100), TP321H (UNS S32109), TP347 (UNS S34700), TP347H (UNS S34709)
StandardsASTM A312, ASTM A213 (for boiler tubes), ASME SA312, EN 10216-5, GB/T 14976
Outer Diameter Range6 mm - 610 mm (1/8 inch - 24 inch)
Wall Thickness0.8 mm - 40 mm (Schedule 10S to Schedule XXS)
LengthFixed lengths up to 12m; cut-to-length service available
Manufacturing ProcessHot finished or cold drawn + Solution annealed + Pickled
Heat TreatmentSolution annealed at 1040-1150°C (grade dependent) followed by water quenching
Surface FinishPickled and passivated, bright annealed, or mechanically polished

High Temperature Properties by Grade

GradeMax Service Temp (Continuous)Max Service Temp (Intermittent)Creep Strength at 600°C (100,000h)Oxidation Resistance
304/304L870°C925°C45 MPaGood (intermittent)
321/321H870°C925°C50 MPaGood (stabilized, less sensitization)
347/347H870°C925°C55 MPaExcellent (Nb-stabilized, superior to 321 in welded condition)
310S1,050°C1,100°C12 MPaSuperior (25% Cr, 20% Ni for extreme oxidation)
Material Selection Guide: Use 321/321H where resistance to intergranular corrosion after welding is critical (Ti-stabilized). Use 347/347H for the highest creep strength and where post-weld heat treatment is impractical (Nb-stabilized). Use 310S for the highest temperature service up to 1,050°C where oxidation resistance - not creep strength - is the primary concern.

Creep and Stress Rupture Data

GradeTest TempStress for Rupture in 10,000hStress for Rupture in 100,000hAllowable Stress at 600°C (ASME B31.3)
TP321H600°C140 MPa95 MPa91 MPa
TP321H650°C82 MPa50 MPa58 MPa
TP347H600°C168 MPa110 MPa98 MPa
TP347H650°C98 MPa62 MPa65 MPa
TP310S700°C35 MPa18 MPa15 MPa

Application Scenarios

Power Generation - Superheater and Reheater Tubes

In coal-fired, gas-fired, and combined-cycle power plants, superheater and reheater tubes operate at steam temperatures of 540-620°C and pressures of 160-250 barg. TP347H is the preferred material for the hottest sections due to its superior creep-rupture strength and resistance to steam-side oxidation. TP321H is commonly specified in intermediate temperature zones (450-540°C) where the Ti-stabilized microstructure prevents sensitization during field welding without requiring post-weld heat treatment.

Petrochemical - Reformer Furnace Tubes and Transfer Lines

Steam methane reforming (SMR) furnaces operate with tube metal temperatures reaching 850-950°C at the hot face. TP310S seamless pipes are used in convection section transfer lines and hot collector headers where high chromium (24-26%) and nickel (19-22%) content provides essential oxidation and carburization resistance in flue gas environments containing CO, CO2, and H2O.

Industrial Boilers - Water Wall and Economizer Piping

High-pressure industrial boilers serving chemical plants, refineries, and district heating networks demand piping that withstands both thermal cycling and internal corrosion from treated boiler feedwater. TP321 and TP321H pipes provide the necessary combination of weldability, creep strength, and resistance to flow-accelerated corrosion (FAC) in two-phase regions.

Heat Recovery Steam Generators (HRSG)

Combined-cycle HRSG units subject tube bundles to rapid temperature transients during daily start-stop cycling. TP347H's niobium-stabilized microstructure and higher creep ductility make it the grade of choice for high-pressure evaporator and superheater harp assemblies. The material tolerates the thermal fatigue associated with frequent cycling better than ferritic grades like T91 in the same temperature range.

Ethylene Cracking Furnaces

Cracking furnace convection sections operate at tube metal temperatures of 700-850°C in hydrocarbon-rich atmospheres. TP310S provides exceptional resistance to metal dusting and carburization - degradation mechanisms that can reduce tube wall thickness by 0.5-1.0 mm/year in lower-grade stainless steels.

Mechanical Properties at Elevated Temperature

PropertyTP321H (20°C)TP321H (600°C)TP347H (20°C)TP347H (600°C)TP310S (20°C)TP310S (800°C)
Tensile Strength (MPa)≥515~380≥515~400≥515~180
Yield Strength (MPa)≥205~140≥205~150≥205~85
Elongation (%)≥35~30≥35~28≥35~45

Quality Assurance

  • Solution Annealing Verification: 100% metallographic examination on sample tubes from each heat to confirm fully recrystallized austenitic grain structure (ASTM grain size 4-7 for H-grade)
  • Grain Size Control: TP321H and TP347H tubes are tested per ASTM E112 to ensure grain size 7 or coarser per ASME SA312 requirements, directly affecting creep performance
  • Stabilization Ratio: For TP321/321H: Ti/C ratio ≥5 per ASTM A312. For TP347/347H: Nb+Ta/C ratio ≥10 per ASTM A312
  • Ultrasonic Testing (UT): 100% UT per ASTM A388/A388M for wall thickness ≥6.35 mm; ASTM E213 for thinner walls
  • Hydrostatic Test: Each pipe tested at 1.5 times the calculated design pressure; extended hold times (30 seconds minimum) applied for heavy-wall pipe
  • Flattening and Flaring Tests: Mechanical workability verified per ASTM A312/A312M on samples from each heat
  • Intergranular Corrosion Test: ASTM A262 Practice E (Strauss test) performed on stabilized grades after sensitizing heat treatment at 675°C for 1 hour to verify Ti/Nb stabilization effectiveness
  • Mill Test Reports: EN 10204 Type 3.1 MTR includes full heat chemistry, mechanical properties at room and elevated temperature, grain size, and stabilization ratio

FAQ

Q: What is the difference between TP321 and TP321H?
TP321H is the high-carbon variant (0.04-0.10% C vs. TP321's max 0.08% C) with controlled grain size (ASTM 7 or coarser) for enhanced creep strength at temperatures above 540°C. For applications below 540°C, TP321 is generally sufficient. For superheater and reheater service above 540°C, TP321H is specified to meet ASME Boiler and Pressure Vessel Code Section II Part D allowable stress values.
Q: Can 310S be used in cyclic thermal service?
310S has excellent resistance to oxidation at temperatures up to 1,050°C continuous, but it should be used with caution in applications involving frequent thermal cycling between ambient and service temperature. The high alloy content makes 310S susceptible to sigma phase embrittlement if held in the 540-900°C range for extended periods during slow cool-down. For cyclic service, we recommend specifying a minimum cooling rate of 100°C/min through the sigma formation range, or selecting a stabilized alternative where the application permits.
Q: What is your minimum order quantity for high-temperature grades?
We accept orders starting from 50 meters per size and grade. For initial qualification, we can supply sample lengths with full MTR documentation. Rush delivery of stock sizes in TP321 and TP347H is typically 5-7 working days.
Q: Do you provide post-weld heat treatment (PWHT) recommendations?
Yes. Every shipment of stabilized grades (321/321H, 347/347H) includes a technical data sheet with qualified welding procedure recommendations, including filler metal selection (ER347 for 347H, ER321 for 321H), interpass temperature limits (≤175°C), and PWHT requirements where applicable. For 347H in thick sections, we recommend solution annealing at 1,080-1,150°C followed by rapid water quenching after welding to restore full creep properties in the HAZ.
Q: How do you verify stabilization effectiveness in Ti and Nb-stabilized grades?
We perform ASTM A262 Practice E (Strauss test) after a sensitizing heat treatment at 675°C for 1 hour. The acceptance criterion is no intergranular cracking or fissuring when the sensitized specimen is bent through 180° over a mandrel diameter equal to the specimen thickness. This test is included in our standard quality control package for all stabilized grade shipments.
Need a material recommendation for your high-temperature piping system? Send us your design temperature, pressure, and service fluid composition. Our application engineers will provide a grade recommendation within 24 hours, complete with ASME allowable stress verification.
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310S 321 347H Stainless Steel Seamless Boiler Tubing for High Temperature Power Generation Applications

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Product Detail
OD Range :
6mm - 610mm (1/8 inch - 24 inch)
Delivery Time :
5-7 days for stock, 15-25 days for mill production
Standard :
ASTM A312, ASTM A213, ASME SA312, EN 10216-5
Stabilization Ratio :
Ti/C ratio >=5 (321/321H), Nb+Ta/C ratio >=10 (347/347H)
Payment Terms :
T/T,L/C,D/P,Western Union
Certification :
ISO 9001, EN 10204 Type 3.1, ASME SA312
Contact Supplier
310S 321 347H Stainless Steel Seamless Boiler Tubing for High Temperature Power Generation Applications

Shanxi Zhongcheng Metal Co., Ltd.

Verified Supplier
1 Years
Shaanxi
Since 2010
Business Type :
Manufacturer, Distributor/Wholesaler, Importer, Exporter, Trading Company, Seller
Main Products :
Colored Stainless Steel Sheet, Incoloy 800, Stainless Steel Pipe
Total Annual :
20000000-50000000
Employee Number :
50~100
Certification Level :
Verified Supplier
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